Research On Seismic Performance Of Knee Braced Beam-to-Column Connections In Steel Frames

Steel beam-column connection is the key part of the structure.If the joint design is not reasonable or defect in its construction,the structure will be failured and collapsed by the earthquake.Therefore,one of the design principles of steel structure seismic is to achieve "strong joint and weak member".Joint seismic design method is commonly used instrengthening joints and weaken the section of beam flange or web.Knee brace joint proposed in this paper is a new type of form of energy consumption joint,The position of the frame beam and the frame column connection is equipped with low strength and good deformation knee brace plate energy consumption.Referred brace energy joint.Unlike the design principle of strengthen joint method.Knee brace is made of low yield point steel,Under the small earthquakes,Knee brace can improve the lateral stiffness of the structure,to meet the requirements of the steel structure system lateral resistance;Under large earthquake,knee-bracing components yield before the main structure,through the plastic deformation of knee brace to shorten the earthquake energy consumption.Steel frame brace energy joint has greater stiffness and good ductility.Overcome the traditional disadvantages of plastic hinge frame beam forming earthquake energy consumption.The plastic deformation control in the knee brace,without damaging the frame beam.It is easy to replace the bolts connecting knee brace and easy to repair.In order to make the knee brace energy consumption of joints used in the steel structures,in need of theoretical research and finite element analysis for the simulation of the energy dissipation mechanism,and through experimental verification.Study on knee brace energy consumption of joints form size and connection structure.Select the single knee brace joint and double knee brace joint of two different forms of knee brace type energy consumption of joints to carry out theoretical research,using the ABAQUS finite element modeling and analysis.On this basis,through quasi static tests on the joints,a comparative analysis of theoretical research and finite element analysis and the experimental results are consistent.Study on the consumption mechanism,failure process and energy dissipation performance of steel structure knee brace joint.The results show that the knee brace will be the first one to enter yield,and has good deformation capacity.Under the premise of the main structural beams and columns,etc.are not damaged,brace can produce large plastic deformation.It can consume seismic energy joint has good ductility and hysteretic behavior,Energy performance of double knee brace joint compared to the single knee brace joint to be more superior.At the same time,both in good agreement,and has proved the rationality and correctness of the finite element model.Based on previous studies,to carry out the research on support parameters affecting the energy consumption performance of steelframe structure corner.In this paper,a analysis for the influence of parameters of steel frame structure knee brace energy consumption type of joint,mainly includes arrangement direction of knee brace eccentricity,joint span-depth ratio,knee brace plate width,knee brace plate thickness.In view of the above factors,this paper established the finite element model of multi group derived from the test model,and analyzes its stiffness degradation and energy dissipation performance,obtained the effect of relative factors,and gives the relevant design recommendations.In this paper,the energy performance of steel frame structure of knee brace joint is systematically studied,and gives the design suggestion and the opinion of relevant,has the important meaning to the theoretical research of knee brace steel frame system,and also an important reference role for engineering applications.